diff --git a/README.md b/README.md
index 5b0ada4e..484ad0f1 100644
--- a/README.md
+++ b/README.md
@@ -63,6 +63,7 @@ For language-specific quick start guides, please refer to the README in each SDK
 | Call [Timeouts](https://docs.inferable.ai/pages/functions#config-timeoutseconds)                         |   ✅    | ❌  |  ❌  |
 | Call [Retries](https://docs.inferable.ai/pages/functions#config-retrycountonstall)                       |   ✅    | ❌  |  ❌  |
 | Call [Approval](https://docs.inferable.ai/pages/functions#config-requiresapproval) (Human in the loop)   |   ✅    | ❌  |  ❌  |
+| Auth Context                                                                                             |   ✅    | ❌  |  ❌  |
 
 ## Documentation
 
diff --git a/sdk-node/src/Inferable.test.ts b/sdk-node/src/Inferable.test.ts
index 9df2e0ef..69e5148f 100644
--- a/sdk-node/src/Inferable.test.ts
+++ b/sdk-node/src/Inferable.test.ts
@@ -90,9 +90,6 @@ describe("Inferable", () => {
         }),
       },
       description: "echoes the input",
-      authenticate: (ctx, args) => {
-        return args.foo === ctx ? Promise.resolve() : Promise.reject();
-      },
     });
 
     expect(d.registeredFunctions).toEqual(["echo"]);
@@ -116,9 +113,6 @@ describe("Inferable", () => {
         }),
       },
       description: "echoes the input",
-      authenticate: (ctx, args) => {
-        return args.foo === ctx ? Promise.resolve() : Promise.reject();
-      },
     });
 
     expect(d.activeServices).toEqual([]);
diff --git a/sdk-node/src/Inferable.ts b/sdk-node/src/Inferable.ts
index 1704460b..3fb4f7b3 100644
--- a/sdk-node/src/Inferable.ts
+++ b/sdk-node/src/Inferable.ts
@@ -8,6 +8,7 @@ import * as links from "./links";
 import { machineId } from "./machine-id";
 import { Service, registerMachine } from "./service";
 import {
+  ContextInput,
   FunctionConfig,
   FunctionInput,
   FunctionRegistration,
@@ -346,11 +347,9 @@ export class Inferable {
       schema,
       config,
       description,
-      authenticate,
     }) => {
       this.registerFunction({
         name,
-        authenticate,
         serviceName: input.name,
         func,
         inputSchema: schema.input,
@@ -413,21 +412,16 @@ export class Inferable {
 
   private registerFunction<T extends z.ZodTypeAny | JsonSchemaInput>({
     name,
-    authenticate,
     serviceName,
     func,
     inputSchema,
     config,
     description,
   }: {
-    authenticate?: (
-      authContext: string,
-      args: FunctionInput<T>,
-    ) => Promise<void>;
     name: string;
     serviceName: string;
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
-    func: (input: FunctionInput<T>) => any;
+    func: (input: FunctionInput<T>, context: ContextInput) => any;
     inputSchema: T;
     config?: FunctionConfig;
     description?: string;
@@ -464,7 +458,6 @@ export class Inferable {
 
     const registration: FunctionRegistration<T> = {
       name,
-      authenticate,
       serviceName,
       func,
       schema: {
diff --git a/sdk-node/src/contract.ts b/sdk-node/src/contract.ts
index 51f4340d..abb81d2c 100644
--- a/sdk-node/src/contract.ts
+++ b/sdk-node/src/contract.ts
@@ -13,7 +13,7 @@ const machineHeaders = {
 };
 
 // Alphanumeric, underscore, hyphen, no whitespace. From 6 to 128 characters.
-const userDefinedIdRegex = /^[a-zA-Z0-9-]{6,128}$/;
+const userDefinedIdRegex = /^[a-zA-Z0-9-_]{6,128}$/;
 
 const functionReference = z.object({
   service: z.string(),
@@ -426,7 +426,7 @@ export const definition = {
             ),
         })
         .optional()
-        .describe("A prompt template which the run should be created from"),
+        .describe("DEPRECATED"),
       reasoningTraces: z
         .boolean()
         .default(true)
@@ -582,7 +582,6 @@ export const definition = {
     responses: {
       200: z.object({
         id: z.string(),
-        jobHandle: z.string().nullable(),
         userId: z.string().nullable(),
         status: z
           .enum(["pending", "running", "paused", "done", "failed"])
@@ -900,6 +899,7 @@ export const definition = {
       runId: z.string(),
     }),
     responses: {
+      404: z.undefined(),
       200: z.object({
         messages: z.array(
           z.object({
@@ -955,7 +955,6 @@ export const definition = {
         ),
         run: z.object({
           id: z.string(),
-          jobHandle: z.string().nullable(),
           userId: z.string().nullable(),
           status: z
             .enum(["pending", "running", "paused", "done", "failed"])
@@ -1232,7 +1231,9 @@ export const definition = {
         z.object({
           id: z.string(),
           data: z.string(),
-          tags: z.array(z.string()),
+          tags: z
+            .array(z.string())
+            .transform((tags) => tags.map((tag) => tag.toLowerCase().trim())),
           title: z.string(),
         }),
       ),
@@ -1252,6 +1253,7 @@ export const definition = {
     query: z.object({
       query: z.string(),
       limit: z.coerce.number().min(1).max(50).default(5),
+      tag: z.string().optional(),
     }),
     responses: {
       200: z.array(
@@ -1275,7 +1277,9 @@ export const definition = {
     headers: z.object({ authorization: z.string() }),
     body: z.object({
       data: z.string(),
-      tags: z.array(z.string()),
+      tags: z
+        .array(z.string())
+        .transform((tags) => tags.map((tag) => tag.toLowerCase().trim())),
       title: z.string(),
     }),
     responses: {
@@ -1396,6 +1400,7 @@ export const definition = {
           id: z.string(),
           function: z.string(),
           input: z.any(),
+          customerAuthContext: z.any().nullable(),
         }),
       ),
     },
diff --git a/sdk-node/src/execute-fn.test.ts b/sdk-node/src/execute-fn.test.ts
index 42698430..9c1468ea 100644
--- a/sdk-node/src/execute-fn.test.ts
+++ b/sdk-node/src/execute-fn.test.ts
@@ -1,54 +1,7 @@
-import { executeFn } from "./execute-fn";
-
 describe("executeFn", () => {
   it("should run a function with arguments", async () => {
     const fn = (val: { [key: string]: string }) => Promise.resolve(val.foo);
     const result = await fn({ foo: "bar" });
     expect(result).toBe("bar");
   });
-
-  it("should authenticate a function with valid context", async () => {
-    const fn = (val: { [key: string]: string }) => Promise.resolve(val.foo);
-    const args = { foo: "bar" };
-    const authenticate = (
-      authContext: string,
-      args: { [key: string]: string },
-    ) => {
-      return args.foo === authContext
-        ? Promise.resolve()
-        : Promise.reject(new Error("Unauthorized"));
-    };
-
-    const result = executeFn(fn, [args], authenticate, "bar");
-
-    await expect(result).resolves.toEqual({
-      content: "bar",
-      functionExecutionTime: expect.any(Number),
-      type: "resolution",
-    });
-  });
-
-  it("should authenticate a function with invalid context", async () => {
-    const fn = (val: { [key: string]: string }) => Promise.resolve(val.foo);
-    const args = { foo: "bar" };
-    const authenticate = (
-      authContext: string,
-      args: { [key: string]: string },
-    ) => {
-      return args.foo === authContext
-        ? Promise.resolve()
-        : Promise.reject(new Error("Unauthorized"));
-    };
-
-    const result = executeFn(fn, [args], authenticate, "not-bar");
-
-    await expect(result).resolves.toEqual(
-      expect.objectContaining({
-        type: "rejection",
-        content: expect.objectContaining({
-          message: "Unauthorized",
-        }),
-      }),
-    );
-  });
 });
diff --git a/sdk-node/src/execute-fn.ts b/sdk-node/src/execute-fn.ts
index 30d0d122..0cd4c8ae 100644
--- a/sdk-node/src/execute-fn.ts
+++ b/sdk-node/src/execute-fn.ts
@@ -1,4 +1,3 @@
-import { InferableError } from "./errors";
 import { serializeError } from "./serialize-error";
 import { FunctionRegistration } from "./types";
 
@@ -11,22 +10,9 @@ export type Result<T = unknown> = {
 export const executeFn = async (
   fn: FunctionRegistration["func"],
   args: Parameters<FunctionRegistration["func"]>,
-  authenticate?: (
-    authContext: string,
-    args: Parameters<FunctionRegistration["func"]>["0"],
-  ) => Promise<void>,
-  authContext?: string,
 ): Promise<Result> => {
   const start = Date.now();
   try {
-    if (authenticate) {
-      if (!authContext) {
-        throw new InferableError(InferableError.JOB_AUTHCONTEXT_INVALID);
-      }
-
-      await authenticate(authContext, args[0]);
-    }
-
     const result = await fn(...args);
 
     return {
diff --git a/sdk-node/src/service.ts b/sdk-node/src/service.ts
index 48386244..a56d062f 100644
--- a/sdk-node/src/service.ts
+++ b/sdk-node/src/service.ts
@@ -16,6 +16,7 @@ type CallMessage = {
   id: string;
   function: string;
   input?: unknown;
+  customerAuthContext?: unknown;
 };
 
 export class Service {
@@ -268,8 +269,9 @@ export class Service {
 
     const result = await executeFn(
       registration.func,
-      [args],
-      registration.authenticate,
+      [args, {
+        customerAuthContext: call.customerAuthContext,
+      }],
     );
 
     await onComplete(result);
diff --git a/sdk-node/src/types.ts b/sdk-node/src/types.ts
index 085acab2..4868bafc 100644
--- a/sdk-node/src/types.ts
+++ b/sdk-node/src/types.ts
@@ -1,6 +1,13 @@
 import { z } from "zod";
 import { FunctionConfigSchema } from "./contract";
 
+/**
+ * Context object which is passed to function calls
+ */
+export type ContextInput = {
+  customerAuthContext?: unknown;
+}
+
 export type FunctionConfig = z.infer<typeof FunctionConfigSchema>;
 
 export type FunctionInput<T extends z.ZodTypeAny | JsonSchemaInput> =
@@ -53,9 +60,8 @@ export type FunctionRegistrationInput<
   T extends z.ZodTypeAny | JsonSchemaInput,
 > = {
   name: string;
-  authenticate?: (authContext: string, args: FunctionInput<T>) => Promise<void>;
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  func: (input: FunctionInput<T>) => any;
+  func: (input: FunctionInput<T>, context: ContextInput) => any;
   schema: FunctionSchema<T>;
   config?: FunctionConfig;
   description?: string;
@@ -96,13 +102,12 @@ export interface FunctionRegistration<
   T extends JsonSchemaInput | z.ZodTypeAny = any,
 > {
   name: string;
-  authenticate?: (authContext: string, args: FunctionInput<T>) => Promise<void>;
   serviceName: string;
   description?: string;
   schema: {
     input: T;
     inputJson: string;
   };
-  func: (args: FunctionInput<T>) => any;
+  func: (args: FunctionInput<T>, context: ContextInput) => any;
   config?: FunctionConfig;
 }